Most of us who are sufficiently versed in Portuguese know that the phrase “vem cá” means “come here” (though, technically, I suppose it should be as a command, ie “venha cá” ). There’s a second meaning which can be loosely translated into English as “hold on”, “wait just a second”, “listen up” or even “pay attention”, all of them serving as a way to call attention to something you wish to say.
Ex. “Vem cá, o que está acontecendo aqui?”
Ex. “Hold on a sec., what’s going on here?”
So how do you tell the difference between someone wanting you to come closer or wanting you to listen up? Aside from understanding the context, the informal usage has a slightly different intonation than the literal one.
In Portuguese, a substitute for “vem cá”, in the informal sense, is the phrase “olha só”. Some people might have an aversion to this secondary usage and may respond by saying “Vem cá pra onde? Eu não estou aqui já!?” (Come where? Am I not already here?).